include/wx/hashmap.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        hashmap.cpp
   3 // Purpose:     wxHashMap class
   4 // Author:      Mattia Barbon
   5 // Modified by:
   6 // Created:     29/01/2002
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Mattia Barbon
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_HASHMAP_H_
  13 #define _WX_HASHMAP_H_
  14
  15 #ifdef __GNUG__
  16 #pragma interface "hashmap.h"
  17 #endif
  18
  19 #include <wx/string.h>
  20
  21 // private
  22 struct WXDLLEXPORT _wxHashTable_NodeBase
  23 {
  24     _wxHashTable_NodeBase() : m_nxt(0) {}
  25
  26     _wxHashTable_NodeBase* m_nxt;
  27 };
  28
  29 // private
  30 class WXDLLEXPORT _wxHashTableBase2
  31 {
  32 public:
  33     typedef void (*NodeDtor)(_wxHashTable_NodeBase*);
  34     typedef unsigned long (*BucketFromNode)(_wxHashTableBase2*,_wxHashTable_NodeBase*);
  35     typedef _wxHashTable_NodeBase* (*ProcessNode)(_wxHashTable_NodeBase*);
  36 protected:
  37     static _wxHashTable_NodeBase* DummyProcessNode(_wxHashTable_NodeBase* node);
  38     static void DeleteNodes( size_t buckets, _wxHashTable_NodeBase** table,
  39                              NodeDtor dtor );
  40     static _wxHashTable_NodeBase* GetFirstNode( size_t buckets,
  41                                                 _wxHashTable_NodeBase** table )
  42     {
  43         for( size_t i = 0; i < buckets; ++i )
  44             if( table[i] )
  45                 return table[i];
  46         return 0;
  47     }
  48
  49     // as static const unsigned prime_count = 31 but works with all compilers
  50     enum { prime_count = 31 };
  51     static const unsigned long ms_primes[prime_count];
  52
  53     // returns the first prime in ms_primes greater than n
  54     static unsigned long GetNextPrime( unsigned long n );
  55
  56     // returns the first prime in ms_primes smaller than n
  57     // ( or ms_primes[0] if n is very small )
  58     static unsigned long GetPreviousPrime( unsigned long n );
  59
  60     static void CopyHashTable( _wxHashTable_NodeBase** srcTable,
  61                                size_t srcBuckets, _wxHashTableBase2* dst,
  62                                _wxHashTable_NodeBase** dstTable,
  63                                BucketFromNode func, ProcessNode proc );
  64
  65     static void** AllocTable( size_t size )
  66     {
  67         return (void **)calloc(size, sizeof(void*));
  68     }
  69 };
  70
  71 #define _WX_DECLARE_HASHTABLE( VALUE_T, KEY_T, HASH_T, KEY_EX_T, KEY_EQ_T, CLASSNAME, CLASSEXP, SHOULD_GROW, SHOULD_SHRINK ) \
  72 CLASSEXP CLASSNAME : protected _wxHashTableBase2 \
  73 { \
  74 public: \
  75     typedef KEY_T key_type; \
  76     typedef VALUE_T value_type; \
  77     typedef HASH_T hasher; \
  78     typedef KEY_EQ_T key_equal; \
  79  \
  80     typedef size_t size_type; \
  81     typedef ptrdiff_t difference_type; \
  82     typedef value_type* pointer; \
  83     typedef const value_type* const_pointer; \
  84     typedef value_type& reference; \
  85     typedef const value_type& const_reference; \
  86     /* should these be protected? */ \
  87     typedef const KEY_T const_key_type; \
  88     typedef const VALUE_T const_mapped_type; \
  89 protected: \
  90     struct Node; \
  91     typedef KEY_EX_T key_extractor; \
  92     typedef CLASSNAME Self; \
  93  \
  94     Node** m_table; \
  95     size_t m_tableBuckets; \
  96     size_t m_items; \
  97     hasher m_hasher; \
  98     key_equal m_equals; \
  99     key_extractor m_getKey; \
 100  \
 101     struct Node:public _wxHashTable_NodeBase \
 102     { \
 103     public: \
 104         Node( const value_type& value ) \
 105             : m_value( value ) {} \
 106         Node* m_next() { return (Node*)this->m_nxt; } \
 107  \
 108         value_type m_value; \
 109     }; \
 110  \
 111     struct Iterator; \
 112     friend struct CLASSNAME::Iterator; \
 113  \
 114     static void DeleteNode( _wxHashTable_NodeBase* node ) \
 115     { \
 116         delete (Node*)node; \
 117     } \
 118  \
 119     /*                  */ \
 120     /* forward iterator */ \
 121     /*                  */ \
 122     struct Iterator \
 123     { \
 124         Node* m_node; \
 125         Self* m_ht; \
 126  \
 127         Iterator() : m_node(0), m_ht(0) {} \
 128         Iterator( Node* node, const Self* ht ) \
 129             : m_node(node), m_ht((Self*)ht) {} \
 130         bool operator ==( const Iterator& it ) const \
 131             { return m_node == it.m_node; } \
 132         bool operator !=( const Iterator& it ) const \
 133             { return m_node != it.m_node; } \
 134     protected: \
 135         Node* GetNextNode() \
 136         { \
 137             size_type bucket = GetBucketForNode(m_ht,m_node); \
 138             for( size_type i = bucket + 1; i < m_ht->m_tableBuckets; ++i ) \
 139             { \
 140                 if( m_ht->m_table[i] ) \
 141                     return m_ht->m_table[i]; \
 142             } \
 143             return 0; \
 144         } \
 145  \
 146         void PlusPlus() \
 147         { \
 148             Node* next = m_node->m_next(); \
 149             m_node = next ? next : GetNextNode(); \
 150         } \
 151     }; \
 152  \
 153 public: \
 154     struct iterator:public Iterator \
 155     { \
 156         iterator() : Iterator() {} \
 157         iterator( Node* node, Self* ht ) : Iterator( node, ht ) {} \
 158         iterator& operator++() { PlusPlus(); return *this; } \
 159         iterator operator++(int) { iterator it=*this;PlusPlus();return it; } \
 160         reference operator *() const { return m_node->m_value; } \
 161         pointer operator ->() const { return &(m_node->m_value); } \
 162     }; \
 163  \
 164     struct const_iterator:public Iterator \
 165     { \
 166         const_iterator() : Iterator() {} \
 167         const_iterator( Node* node, const Self* ht ) \
 168             : Iterator( node, (Self*)ht ) {} \
 169         const_iterator& operator++() { PlusPlus();return *this; } \
 170         const_iterator operator++(int) { const_iterator it=*this;PlusPlus();return it; } \
 171         const_reference operator *() const { return m_node->m_value; } \
 172         const_pointer operator ->() const { return &(m_node->m_value); } \
 173     }; \
 174  \
 175     CLASSNAME( size_type size = 10, const hasher& hfun = hasher(), \
 176                const key_equal& k_eq = key_equal(), \
 177                const key_extractor& k_ex = key_extractor() ) \
 178         : m_tableBuckets( GetNextPrime( size ) ), \
 179           m_items( 0 ), \
 180           m_hasher( hfun ), \
 181           m_equals( k_eq ), \
 182           m_getKey( k_ex ) \
 183     { \
 184         m_table = (Node**)AllocTable( m_tableBuckets ); \
 185     } \
 186  \
 187     CLASSNAME( const Self& ht ) \
 188         : m_table( 0 ), \
 189           m_tableBuckets( 0 ), \
 190           m_items( ht.m_items ), \
 191           m_hasher( ht.m_hasher ), \
 192           m_equals( ht.m_equals ), \
 193           m_getKey( ht.m_getKey ) \
 194     { \
 195         HashCopy( ht ); \
 196     } \
 197  \
 198     const Self& operator=( const Self& ht ) \
 199     { \
 200          clear(); \
 201          m_hasher = ht.m_hasher; \
 202          m_equals = ht.m_equals; \
 203          m_getKey = ht.m_getKey; \
 204          m_items = ht.m_items; \
 205          HashCopy( ht ); \
 206          return *this; \
 207     } \
 208  \
 209     ~CLASSNAME() \
 210     { \
 211         clear(); \
 212  \
 213         free(m_table); \
 214     } \
 215  \
 216     hasher hash_funct() { return m_hasher; } \
 217     key_equal key_eq() { return m_equals; } \
 218  \
 219     /* removes all elements from the hash table, but does not */ \
 220     /* shrink it ( perhaps it should ) */ \
 221     void clear() { DeleteNodes( m_tableBuckets, (_wxHashTable_NodeBase**)m_table, DeleteNode ); } \
 222  \
 223     size_type size() const { return m_items; } \
 224     size_type max_size() const { return size_type(-1); } \
 225     bool empty() const { return size() == 0; } \
 226  \
 227     const_iterator end() const { return const_iterator( 0, this ); } \
 228     iterator end() { return iterator( 0, this ); } \
 229     const_iterator begin() const \
 230         { return const_iterator( (Node*)GetFirstNode( m_tableBuckets, (_wxHashTable_NodeBase**)m_table ), this ); }; \
 231     iterator begin() \
 232         { return iterator( (Node*)GetFirstNode( m_tableBuckets, (_wxHashTable_NodeBase**)m_table ), this ); }; \
 233  \
 234     size_type erase( const const_key_type& key ) \
 235     { \
 236         Node** node = GetNodePtr( key ); \
 237  \
 238         if( !node ) \
 239             return 0; \
 240  \
 241         --m_items; \
 242         Node* temp = (*node)->m_next(); \
 243         delete *node; \
 244         (*node) = temp; \
 245         if( SHOULD_SHRINK( m_tableBuckets, m_items ) ) \
 246             ResizeTable( GetPreviousPrime( m_tableBuckets ) - 1 ); \
 247         return 1; \
 248     } \
 249  \
 250 protected: \
 251     static size_type GetBucketForNode( Self* ht, Node* node ) \
 252     { \
 253         return ht->m_hasher( ht->m_getKey( node->m_value ) ) \
 254             % ht->m_tableBuckets; \
 255     } \
 256     static Node* CopyNode( Node* node ) { return new Node( *node ); } \
 257  \
 258     Node* GetOrCreateNode( const value_type& value ) \
 259     { \
 260         const const_key_type& key = m_getKey( value ); \
 261         size_t bucket = m_hasher( key ) % m_tableBuckets; \
 262         Node* node = m_table[bucket]; \
 263  \
 264         while( node ) \
 265         { \
 266             if( m_equals( m_getKey( node->m_value ), key ) ) \
 267                 return node; \
 268             node = node->m_next(); \
 269         } \
 270  \
 271         node = new Node( value ); \
 272         node->m_nxt = m_table[bucket]; \
 273         m_table[bucket] = node; \
 274  \
 275         /* must be after the node is inserted */ \
 276         ++m_items; \
 277         if( SHOULD_GROW( m_tableBuckets, m_items ) ) \
 278             ResizeTable( m_tableBuckets ); \
 279  \
 280         return node; \
 281     } \
 282  \
 283     /* returns NULL if not found */ \
 284     Node** GetNodePtr( const const_key_type& key ) const \
 285     { \
 286         unsigned long hash = m_hasher( key ); \
 287         Node** node = &m_table[hash % m_tableBuckets]; \
 288  \
 289         while( *node ) \
 290         { \
 291             if( m_equals( m_getKey( (*node)->m_value ), key ) ) \
 292                 return node; \
 293             node = (Node**)&(*node)->m_nxt; \
 294         } \
 295  \
 296         return 0; \
 297     } \
 298  \
 299     /* returns NULL if not found */ \
 300     /* expressing it in terms of GetNodePtr is 5-8% slower :-( */ \
 301     Node* GetNode( const const_key_type& key ) const \
 302     { \
 303         unsigned long hash = m_hasher( key ); \
 304         Node* node = m_table[hash % m_tableBuckets]; \
 305  \
 306         while( node ) \
 307         { \
 308             if( m_equals( m_getKey( node->m_value ), key ) ) \
 309                 return node; \
 310             node = node->m_next(); \
 311         } \
 312  \
 313         return 0; \
 314     } \
 315  \
 316     void ResizeTable( size_t newSize ) \
 317     { \
 318         newSize = GetNextPrime( newSize ); \
 319         Node** srcTable = m_table; \
 320         size_t srcBuckets = m_tableBuckets; \
 321         m_table = (Node**)AllocTable( newSize ); \
 322         m_tableBuckets = newSize; \
 323  \
 324         CopyHashTable( (_wxHashTable_NodeBase**)srcTable, srcBuckets, \
 325                        this, (_wxHashTable_NodeBase**)m_table, \
 326                        (BucketFromNode)&GetBucketForNode,\
 327                        (ProcessNode)&DummyProcessNode ); \
 328         free(srcTable); \
 329     } \
 330  \
 331     /* this must be called _after_ m_table has been cleaned */ \
 332     void HashCopy( const Self& ht ) \
 333     { \
 334         ResizeTable( ht.size() ); \
 335         CopyHashTable( (_wxHashTable_NodeBase**)ht.m_table, ht.m_tableBuckets,\
 336                        (_wxHashTableBase2*)this, \
 337                        (_wxHashTable_NodeBase**)m_table, \
 338                        (BucketFromNode)&GetBucketForNode, \
 339                        (ProcessNode)&CopyNode ); \
 340     } \
 341 };
 342
 343 // defines an STL-like pair class CLASSNAME storing two fields: first of type
 344 // KEY_T and second of type VALUE_T
 345 #define _WX_DECLARE_PAIR( KEY_T, VALUE_T, CLASSNAME, CLASSEXP ) \
 346 CLASSEXP CLASSNAME \
 347 { \
 348 public: \
 349     typedef KEY_T t1; \
 350     typedef VALUE_T t2; \
 351     typedef const KEY_T const_t1; \
 352     typedef const VALUE_T const_t2; \
 353  \
 354     CLASSNAME( const const_t1& f, const const_t2& s ):first(t1(f)),second(t2(s)) {} \
 355     CLASSNAME( const const_t1& f ):first(t1(f)),second(t2()) {} \
 356  \
 357     t1 first; \
 358     t2 second; \
 359 };
 360
 361 // defines the class CLASSNAME returning the key part (of type KEY_T) from a
 362 // pair of type PAIR_T
 363 #define _WX_DECLARE_HASH_MAP_KEY_EX( KEY_T, PAIR_T, CLASSNAME, CLASSEXP ) \
 364 CLASSEXP CLASSNAME \
 365 { \
 366 public: \
 367     CLASSNAME() { } \
 368     KEY_T operator()( PAIR_T pair ) const { return pair.first; } \
 369     \
 370     /* the dummy assignment operator is needed to suppress compiler */ \
 371     /* warnings from hash table class' operator=(): gcc complains about */ \
 372     /* "statement with no effect" without it */ \
 373     CLASSNAME& operator=(const CLASSNAME&) { return *this; } \
 374 };
 375
 376 // grow/shrink predicates
 377 inline bool never_grow( size_t, size_t ) { return FALSE; }
 378 inline bool never_shrink( size_t, size_t ) { return FALSE; }
 379 inline bool grow_lf70( size_t buckets, size_t items )
 380 {
 381     return float(items)/float(buckets) >= 0.85;
 382 }
 383
 384 // ----------------------------------------------------------------------------
 385 // hashing and comparison functors
 386 // ----------------------------------------------------------------------------
 387
 388 // NB: implementation detail: all of these classes must have dummy assignment
 389 //     operators to suppress warnings about "statement with no effect" from gcc
 390 //     in the hash table class assignment operator (where they're assigned)
 391
 392 // integer types
 393 class WXDLLEXPORT wxIntegerHash
 394 {
 395 public:
 396     wxIntegerHash() { }
 397     unsigned long operator()( long x ) const { return (unsigned long)x; }
 398     unsigned long operator()( unsigned long x ) const { return x; }
 399     unsigned long operator()( int x ) const { return (unsigned long)x; }
 400     unsigned long operator()( unsigned int x ) const { return x; }
 401     unsigned long operator()( short x ) const { return (unsigned long)x; }
 402     unsigned long operator()( unsigned short x ) const { return x; }
 403
 404     wxIntegerHash& operator=(const wxIntegerHash&) { return *this; }
 405 };
 406
 407 class WXDLLEXPORT wxIntegerEqual
 408 {
 409 public:
 410     wxIntegerEqual() { }
 411     bool operator()( long a, long b ) const { return a == b; }
 412     bool operator()( unsigned long a, unsigned long b ) const { return a == b; }
 413     bool operator()( int a, int b ) const { return a == b; }
 414     bool operator()( unsigned int a, unsigned int b ) const { return a == b; }
 415     bool operator()( short a, short b ) const { return a == b; }
 416     bool operator()( unsigned short a, unsigned short b ) const { return a == b; }
 417
 418     wxIntegerEqual& operator=(const wxIntegerEqual&) { return *this; }
 419 };
 420
 421 // pointers
 422 class WXDLLEXPORT wxPointerHash
 423 {
 424 public:
 425     wxPointerHash() { }
 426
 427     // TODO: this might not work well on architectures with 64 bit pointers but
 428     //       32 bit longs, we should use % ULONG_MAX there
 429     unsigned long operator()( const void* k ) const { return (unsigned long)k; }
 430
 431     wxPointerHash& operator=(const wxPointerHash&) { return *this; }
 432 };
 433
 434 class WXDLLEXPORT wxPointerEqual
 435 {
 436 public:
 437     wxPointerEqual() { }
 438     bool operator()( const void* a, const void* b ) const { return a == b; }
 439
 440     wxPointerEqual& operator=(const wxPointerEqual&) { return *this; }
 441 };
 442
 443 // wxString, char*, wxChar*
 444 class WXDLLEXPORT wxStringHash
 445 {
 446 public:
 447     wxStringHash() {}
 448     unsigned long operator()( const wxString& x ) const
 449         { return wxCharStringHash( x.c_str() ); }
 450     unsigned long operator()( const wxChar* x ) const
 451         { return wxCharStringHash( x ); }
 452     static unsigned long wxCharStringHash( const wxChar* );
 453 #if wxUSE_UNICODE
 454     unsigned long operator()( const char* x ) const
 455         { return charStringHash( x ); }
 456     static unsigned long charStringHash( const char* );
 457 #endif // wxUSE_UNICODE
 458
 459     wxStringHash& operator=(const wxStringHash&) { return *this; }
 460 };
 461
 462 class WXDLLEXPORT wxStringEqual
 463 {
 464 public:
 465     wxStringEqual() {}
 466     bool operator()( const wxString& a, const wxString& b ) const
 467         { return a == b; }
 468     bool operator()( const wxChar* a, const wxChar* b ) const
 469         { return wxStrcmp( a, b ) == 0; }
 470 #if wxUSE_UNICODE
 471     bool operator()( const char* a, const char* b ) const
 472         { return strcmp( a, b ) == 0; }
 473 #endif // wxUSE_UNICODE
 474
 475     wxStringEqual& operator=(const wxStringEqual&) { return *this; }
 476 };
 477
 478 #define _WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME, CLASSEXP ) \
 479 _WX_DECLARE_PAIR( KEY_T, VALUE_T, CLASSNAME##_wxImplementation_Pair, CLASSEXP ) \
 480 _WX_DECLARE_HASH_MAP_KEY_EX( KEY_T, CLASSNAME##_wxImplementation_Pair, CLASSNAME##_wxImplementation_KeyEx, CLASSEXP ) \
 481 _WX_DECLARE_HASHTABLE( CLASSNAME##_wxImplementation_Pair, KEY_T, HASH_T, CLASSNAME##_wxImplementation_KeyEx, KEY_EQ_T, CLASSNAME##_wxImplementation_HashTable, CLASSEXP, grow_lf70, never_shrink ) \
 482 CLASSEXP CLASSNAME:public CLASSNAME##_wxImplementation_HashTable \
 483 { \
 484 public: \
 485     typedef VALUE_T mapped_type; \
 486  \
 487     CLASSNAME( size_type hint = 100, hasher hf = hasher(), key_equal eq = key_equal() ) \
 488         : CLASSNAME##_wxImplementation_HashTable( hint, hf, eq, CLASSNAME##_wxImplementation_KeyEx() ) {} \
 489  \
 490     mapped_type& operator[]( const const_key_type& key ) \
 491     { \
 492         return GetOrCreateNode( CLASSNAME##_wxImplementation_Pair( key ) )->m_value.second; \
 493     } \
 494  \
 495     const_iterator find( const const_key_type& key ) const \
 496     { \
 497         return const_iterator( GetNode( key ), this ); \
 498     } \
 499  \
 500     iterator find( const const_key_type& key ) \
 501     { \
 502         return iterator( GetNode( key ), this ); \
 503     } \
 504  \
 505     void insert( const value_type& v ) { (*this)[v.first] = v.second; } \
 506  \
 507     size_type erase( const key_type& k ) \
 508         { return CLASSNAME##_wxImplementation_HashTable::erase( k ); } \
 509     void erase( const iterator& it ) { erase( it->first ); } \
 510     void erase( const const_iterator& it ) { erase( it->first ); } \
 511  \
 512     /* count() == 0 | 1 */ \
 513     size_type count( const const_key_type& key ) \
 514         { return GetNode( key ) ? 1 : 0; } \
 515 };
 516
 517 // these macros are to be used in the user code
 518 #define WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME) \
 519     _WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME, class )
 520
 521 #define WX_DECLARE_STRING_HASH_MAP( VALUE_T, CLASSNAME ) \
 522     _WX_DECLARE_HASH_MAP( wxString, VALUE_T, wxStringHash, wxStringEqual, \
 523                           CLASSNAME, class );
 524
 525 #define WX_DECLARE_VOIDPTR_HASH_MAP( VALUE_T, CLASSNAME ) \
 526     _WX_DECLARE_HASH_MAP( void*, VALUE_T, wxPointerHash, wxPointerEqual, \
 527                           CLASSNAME, class );
 528
 529 // and these do exactly the same thing but should be used inside the
 530 // library
 531 #define WX_DECLARE_EXPORTED_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME) \
 532     _WX_DECLARE_HASH_MAP( KEY_T, VALUE_T, HASH_T, KEY_EQ_T, CLASSNAME, class WXDLLEXPORT )
 533
 534 #define WX_DECLARE_EXPORTED_STRING_HASH_MAP( VALUE_T, CLASSNAME ) \
 535     _WX_DECLARE_HASH_MAP( wxString, VALUE_T, wxStringHash, wxStringEqual, \
 536                           CLASSNAME, class WXDLLEXPORT );
 537
 538 #define WX_DECLARE_EXPORTED_VOIDPTR_HASH_MAP( VALUE_T, CLASSNAME ) \
 539     _WX_DECLARE_HASH_MAP( void*, VALUE_T, wxPointerHash, wxPointerEqual, \
 540                           CLASSNAME, class WXDLLEXPORT );
 541
 542 #endif // _WX_HASHMAP_H_
 543